1. Field of the Invention
The present invention relates to endoscopic systems. More particularly, this invention pertains to apparatus for maintaining a sterile environment while performing diagnosis and/or surgery by means of an otherwise-conventional endoscopic system of the type that includes an endoscope, a fiber-optic light guide cable and a camera.
2. Description of the Prior Art
The uses of endoscopy have expanded greatly over the past few years. Endoscopic procedures minimize the trauma to the patient and accordingly lessen the amount of patient time required, both in and out of the hospital. Recently, endoscopy has gained widespread acceptance throughout so-called "general" surgery. For example, laparoscopic cholecystectomies (removal of the gall bladder) are now common procedures.
In performing endoscopic general surgery, a camera head must be employed to process the images of internal organs that are transmitted through the optical system of the endoscope. Such a camera permits all members of the surgical team to view the same anatomical site simultaneously. By producing the image on a video screen, the auxiliary video mechanisms of endoscopy effectively replace the much larger incisions of conventional surgery with relatively insignificant punctures.
The complete endoscopic system, which generally includes an endoscope, an optical adapter, a camera head with attached cable and a fiber optic light guide cable for transmitting optical energy from a light source and an electrical cable for communicating with the camera's electronics, is maintained in close proximity to the patient throughout endoscopic procedures. Such components comprise an amalgam of stainless steel, brass, glass, solder, electronic components and rubber parts. The differing natures of these compositions ultimately limit the safety of endoscopic procedures as the instruments themselves can contribute to the risk of infection.
Generally, surgical instruments are sterilized between cases by means of an autoclave that subjects them to sufficiently extreme pressures and temperatures to prevent the survival of biological organisms. Unfortunately, the combination of disparate materials employed within a conventional endoscopic system does not permit autoclaving between surgical cases due to the widely varying rates of thermally-induced expansion and contraction. Such differences can stress electronic components, seals and glass to the breaking point. Other methods, such as exposure to ethylene oxide (gas) or gamma radiation require long sterilization cycles that are inappropriate for inter-case use.
As a result, endoscopes are disinfected, but not sterilized between procedures. Generally disinfection is more than sufficient to protect the patient and the doctor from infection, killing most surface bacteria, viruses and spores. However, some resistant bacteria, viruses and pathogenic spores can remain. There exists evidence, for example, that disinfection may not significantly kill hepatitis B and HIV viruses and is therefore not sufficient in today's world of resistant bacteria and viruses.